One such valve timing control device for an internal combustion engine, has been disclosed in the following prior-art Patent document 1, previously filed by the same applicant as the present invention.
In the valve timing control device disclosed in the Patent document 1, a cover member is provided at the front end side of a motor housing of an electric motor with a prescribed clearance. A pair of electricity-feeding slip rings, facing the clearance, are fixed onto the inner face of the cover member. Also provided or installed on an electricity-feeding plate, which is fixed to the front end section of the motor housing, are electricity-feeding brushes in sliding-contact with the respective slip rings for electricity-feeding to coils of the electric motor.
A rotation detection mechanism is provided between one axial end of a motor output shaft of the electric motor, facing the cover member, and the cover member axially opposing to the one axial end, for detecting a rotational angle of the motor output shaft.
The rotation detection mechanism is an electromagnetic induction type, and has a detected unit fixed to the one axial end of the motor output shaft and a detecting unit fixed to the cover member at a position opposed to a top end of the detected unit. A detected rotor, which is fixed to the top end face of the detected unit, is arranged to be opposed to a receiving circuit (a receiving coil) and an oscillating circuit (an oscillation coil) of the detecting unit with a minute clearance.